The present invention relates to seals used in compressors, such as dual-stage or series compressors used in fuel cell applications.
Air compressors can be used to increase the efficiency of a fuel cell by providing compressed air to the cathode side of the fuel cell. A dual-stage compressor may be used in some applications requiring a higher pressure at the outlet by compressing a volume of air in stages. In a dual-stage compressor, a low pressure compressor wheel is provided on a shaft, and a high pressure compressor wheel is provided on the same shaft. The shaft may be motor-driven, and rotation of the shaft may serve to rotate the compressor wheels. In this way, air at atmospheric temperature and pressure entering the low pressure side of the dual-stage compressor is compressed to a first pressure. The compressed air is then passed on to the high pressure side for a further increase in pressure. The air from the high pressure side of the dual-stage compressor is then delivered to the fuel cell to promote the fuel cell reaction.
Regardless of the particular configuration of the compressor, whether single-stage or dual-stage, the compressor generally defines various flow paths for air at different pressures.